1. Field of the invention
The invention relates to a sprinkler nozzle of the kind having a sprinkler housing with an inlet for liquid and with a longitudinally extending axis, the nozzle housing opposite the inlet being delimited by a surface of revolution with nozzle outlet openings arranged around the axis and wherein, opposite the mouth of the nozzle outlet openings, respective impact faces are arranged for the liquid that flows out through the nozzle outlet openings. Such a sprinkler nozzle is known from DE-U-200 02 324, which is incorporated herein in its entirety by the present reference.
2. Description of the Related Art
Water in the form of small droplets has proven to be an effective way of extinguishing fires by permanently installed equipment, since the small water small droplets evaporate easily and thus provide a high degree of cooling and large amounts of inactive water vapour.
Most prior art systems form small droplets by conveying highly pressurised water (50–200 bar) through nozzle outlet openings in a nozzle housing. A few other systems form small droplets by conveying water through a venturi opening or by causing two water jets to hit each other.
Nozzles are also known, wherein a water jet hits an impact face and wherein the water reflected from the impact face is hit by a second water jet. Such nozzles are primarily intended for reducing the amount of dust contained in the air and have no optimised construction to enable them to be used as permanently installed fire-extinguishing nozzles, including use as automatically released fire extinguishing nozzles. One example of such nozzle is shown in U.S. Pat. No. 2,701,165, wherein the nozzle has a single nozzle outlet opening that extends centrally in extension of the longitudinal axis of the nozzle housing, and wherein the end of a thread is situated opposite the mouthing of the nozzle outlet opening. DE-A-26 49 977 teaches another example, wherein a nozzle housing with a number of nozzle outlet openings has a disc-shaped plate located in front of it that forms an impact face for liquid that flows through each of the nozzle outlet openings. This construction is inconvenient due to the disc-shaped plate shielding against the liquid thus transformed into small droplets. Thereby the nozzle will not be suitable for extinguishing fires, since liquid dispersed to small droplets will not flow to the area centrally in front of the nozzle. Both U.S. Pat. No. 2,701,165 and DE-A-26 49 977 are incorporated herein in their entirety by the present reference.